After graduating cum laude from Harvard Law School in 1972, Professor Brook joined a general corporate practice firm in Boston. In 1975, he was awarded a Bigelow Teaching Fellowship at the University of Chicago Law School and found teaching law students the art of research and legal writing extremely rewarding. Offered a position at New York Law School in 1976, he came to New York, a city in which he had always wanted to live, to use his legal training in a way he had always found most personally rewarding — teaching.

Professor Brook's field is commercial law, and it is his first-year classes that he consistently finds most interesting and challenging. About 10 years ago, Professor Brook began writing the first of his three very successful Examples and Explanations books for Aspen Publishing on three major areas of law: secured transactions, payment systems, and sales and leases. His first book, A Lawyer's Guide to Probability and Statistics (Carswell, 1990), utilized his math background — he was a Phi Beta Kappa math major at Harvard — to shed some light on a field where a great deal of fact-finding and proof in litigation is based on probability and statistics. A 1981–82 Finkelstein Fellow at Columbia Law School, where he pursued studies in the area of probability and statistics and the law, he received his LL.M. from Columbia in 1983. Professor Brook's Examples and Explanations books, which he updates approximately every three years, rely on his colloquial and humorous style of writing and teaching, a style that he maintains makes commercial law far more accessible and less intimidating than it might otherwise be. His most recent addition to the collection is Secured Transactions: Examples & Explanations, Fourth Edition (Aspen Publishing, 2008).